1. Field of the Invention
The present invention relates to electromagnetic energy heating, and more .[.particular.]. .Iadd.particularly.Iaddend., is directed towards methods and apparatuses for controlling the fluency of high .[.viscous.]. .Iadd.viscosity .Iaddend.hydrocarbon fluids.
2. Description of the prior Art
Commercial and industrial oil burners have been designed for use with either distillate grades such as No. 2 and No. 4 fuel oils or residual grades such as No. 5 heavy and No. 6 fuel oils. The low viscosity distillate grades are sufficiently fluid at normal ambient temperatures for good burner operation in typical commercial and industrial installations. The high viscosity residual grades are not sufficiently fluid at normal ambient temperatures, whereby preheating and continuous circulation at temperatures above .[.it.]. .Iadd.its .Iaddend.pour point at all stages between a storage tank and .Iadd.oil .Iaddend.burner is required to assure pumpability. The BTU content of the residual grades is greater than that of the more highly refined distillate grades and the cost of the residual grades is less than the cost of the distillate grades. Some of the factors that have limited the use of the residual grades of fuel oil are the high labor and equipment costs in using such fuel oil as well as the preheating expenses. The use of steam, hot water, gas and electricity for preheating residual grade fuel oils has been introduced with varying degrees of success.